The program atop is an interactive monitor to view the load on a Linux system. It shows the occupation of the most critical hardware resources (from a performance point of view) on system level, i.e. cpu, memory, disk and network.
It also shows which processes are responsible for the indicated load with respect to cpu- and memory load on process level. Disk load is shown if per process “storage accounting” is active in the kernel or if the kernel patch ‘cnt’ has been installed. Network load is only shown per process if the kernel patch ‘cnt’ has been installed.
Every interval (default: 10 seconds) information is shown about the resource occupation on system level (cpu, memory, disks and network layers), followed by a list of processes which have been active during the last interval (note that all processes that were unchanged during the last interval are not shown, unless the key ‘a’ has been pressed). If the list of active processes does not entirely fit on the screen, only the top of the list is shown (sorted in order of activity).
The intervals are repeated till the number of samples (specified as command argument) is reached, or till the key ‘q’ is pressed in interactive mode.
cp <latest file> /tmp/<here>
atop -r /tmp/atop_app03s_20121001
Define start time using B command